A pimple behind the pads of a cat’s front paws may be due to tinea felis. The inside of a cat’s paws is most likely to be infected by Western fungi. You can buy medicines to treat tinea felis to treat the cat, or send the cat to a pet hospital. Let professionals treat it, and during this period, you can supplement the cat’s nutrition and let the cat get more sun, so that the cat’s ringworm can be cured faster.